The Cross legged Knight by Candace Robb.
This is an 'Owen Archer' mystery. Set in England in 1371, it begins with the tale of the Bishop of Winchester's near 'accident' in the grounds of York Minster . The story then enfolds with a fire in a townhouse in York where the body of a young woman was found. Owen Archer, a one -eyed spy is asked to solve the mystery of the fire. With the help of his wife and Magda a 'natural ' healer from the riverside a complex tale is discovered. This is a really good read, you can just about smell Medieval York. I think it's no. 8 in the 'Owen Archer' novels , I intend to read more.
The curious title is the name of a carving placed onto coffins of Christians who died for their faith, in this instance someone who has been on a Holy Crusasde.